This was a multi-center, multiple dose study in patients with moderate to severe psoriasis (a randomized, placebo-controlled, double-blind, serial 4 panel design). Dose levels included initially 0.15 mg/kg, 0.30 mg, and 0.45 mg/kg q 12 hr. for 2 weeks. Based on results from these, the best dosage schedule for the study drug was to be chosen and patients were to be randomized to receive study drug, placebo or cyclosporine for 8 weeks. However, based on results from the first part of the study the second part of the protocol was modified. The higher dose was reduced to 0.26 mg/kg q 12 hr. and the treatment time was extended to 12 weeks. This protocol was continued as a multicenter randomized, double-blinded, parallel-group multiple oral dose study to evaluate the tolerability and efficacy of L-733725 versus cyclosporine A versus placebo in the treatment of patients with moderate to severe chronic plaque-type psoriasis.